On the Connection Between Continent Scale Rates of Lightning and Solar Wind Sector Structures

Abstract:

Recent research has highlighted an unexpected observational connection between terrestrial lightning storms and characteristics of the sector structures in the interplanetary magnetic field. For example, work by Owens et al. (2014) showed that lightning and thunder rates in the United Kingdom between 2000 and 2007 were 40-60% greater when the heliospheric magnetic field (HMF) was directed towards the sun. Here we investigate the connection between these solar wind sector structures and the rates of lightning across the whole globe and in different regional geographic areas between 2010 and 2019. Using OMNI solar wind data, we characterised the prevailing direction of the HMF as either towards or away from the sun, separated by crossings of the heliospheric current sheet. Binning World Wide Lightning Location Network (WWLLN) data into hourly and geographical bins, we assigned a direction to each bin. Initial results show that for a geographic region encompassing the UK, and between 2010 and 2014, the Owens et al. result of an increase in lightning rates is also largely present for these years as well, with the exception of 2012 where rates are similar. Expanded results showing global and regional results from equatorial, mid- and polar latitudes and for each continent will be presented, to assess if this result also holds globally and/or in other geographic regions of the world. Or, if this phenomenon is localised to smaller regions such as encompassing the UK, perhaps as a result of small changes to global weather patterns acting to produce a significantly amplified local effect as a result of large proximal gradients.